* {
    margin: 0;
    padding: 0;
}

body {
    background: url(https://img.zcool.cn/community/01714a5c5901b1a801203d223f67e1.jpg@1280w_1l_2o_100sh.jpg) no-repeat;
    background-size: cover;
    height: 100vh;
}

#canvas {
    margin: auto;
    display: block;
    box-shadow: 0 5px 5px rgba(0, 0, 0, .5);
}
.restart{
    display: none;
    width: 600px;
    position:absolute;
    text-align: center;

    left: 50%;
    top: 50%;

    transform: translate(-50%, -50%);

    font-size: 40px;
    color: #ffd95b;

    text-shadow: 0 5px 5px rgba(0, 0, 0, .3);
}

.restart .restart-btn{
    display: inline-block;
    width: 250px;
    height: 80px;

    line-height: 80px;
    color: #fff;

    background-color: #ffd95b;

    border-radius: 40px;
    cursor: pointer;

    margin-top: 50px;
    box-shadow: 0 5px 5px rgba(0, 0, 0, .3);

    font-size: 25px;

}